Pneumatic-dispatch-tube apparatus



Fe 1 19 l .K b 27 J. G. MAcLARr-:N

PNEUMATIC DISPATCH TUBE APPARATUS Y Filed April 6, 1920 2 SheeJcs-SheeI l lllllll INVENTOR Feb. 1, 1927.

- J. G. MACLAREN PNEUMATIC DISPATCH TUBE APPARATUS Filed April 6,1920 2 sheets-Sheet 2 INVENTR ATTORNEY Patented Feb. 1, 1927.

JAVESG. MACLAREhT-GF MAIJARONEC-Ku NEW YORK, ASSGNOR, BY IVIESEE` ASS-"IGN- IVIENTS, '110 THE LAMSON CO-lLPiNY,l A CORPORATON OF MASSACHUSETTS.

PNEUMATcLDsrATcH-runn Argentiniens.

Application led'April 6, 1920.

This invention relates to' pneumatic car'- rier sy`stem`s`,being more especially conceri'ied with pneumatic dispatch tube apparatus ot that class in which' a siirgle transit tube is used tor the transn'iissiou' of carriers' in opposite directions, and more particularly, systems oithe type in which an air pressure above that ot the atmosphere is utilized' tor the propulsion ot the carriers.

My invention will be best understood by rcterence to the following description, when taken in connection with the accompanying drawings, whileY its scope will bemore particularly pointed out in the appended claims.

ln the drawings; Figure 1 is a plan view vith one side sectioned onltlite linele-l in' Figure-3. Figur`e2 is a'sectional elevation on line 2-2 in Figure 1, and.` there also shown in this figure'.l an elevation ofthe timing dash pot to illustrateiits location inrelation to other parts. Figure 3 isan end elevation including a" sectional view ot the timing dash pot. Figure i isa sectional plan of the main casting, along line Vin Figure 3. Fig; 5 is aview partly in si'de elevation and partly in section showing in detail a minimum pressure release valve mechanism, and Figure 6 is adiagram showVn ing one form ofa pressure pneumatic dispatch tube system. I

Referring to the drawings, andn to the embodiment ot my invention which is"`ill`ustrated therein', l have 'diagrammed in Figure (S, a pneumatic dispatch tube apparatus, comprisin'g'a transit t'ube 9 connecting two terminals 10, which may bekand are herein, identical in construction, though' one is arranged or upward and the other for downward discharge of carriers. Flach of these terminals is herein equipped with a'chute 11A ot' the usual construction to check the speed of the emerging carrier, and to assist `in bringing the latter to rest at a suitable point.

As' a means for supplying anair current' lor the propulsion ot the carriers-through the transit tube". l have herein provided'1 a power driven air compressor' 12, which der livers compressed air throil'gh a pipe 13 into sei-iai uc. 371,729;

a tank 14, having an outlet `piperl leading to a l'nressure regulatingvalw'fe 16, of' which there are'mai'iy makes availableiii the open market, whence' branch pipes 17 lead' t'o the' respective terminals 10.

Since the .latter are hereinA oit identical constructiong-a detailed description' ot one 5 will" sutliee lor' both. A

Referring now more particularly to Figur'es 1 to d, inclusive, the terminal 10 is provided w'itlia' chamber 18 commuuic'atingin any suitable manner with the transit tube 9, the latter to'r this purpose being herein pro-f vided with one orE more per'orations 19. Communication between the air' supply pipe" 17 and tlietransit' tube 9 maybe controlled by any suitable valve, such for example, asa' valve' 2O hereinafter' called the air inlet valve, thelatter cooperatingwith a' suitable seat 21, and having a stem 22 mounted to' slide vertically in a guide' 23: Amy 'suitable means'may be provided tornormallyA hblding 70 tli'e valve 2O seated, but herein Ihafv'e provided Va `helical spring 2a-encircling' the;- valve" stem and serving in obvious nianner'to assist the' air pressure in holding the valyeV seated except when" it is purposely'opened.

As af means tor closing the carrier inlet (and outlet) of the transit tube, -have herein provided a suitable closure 25, usually called a door, ot common form, usually made of' rubber or some other suitable more or less yielding materiavl secured to a reinforcing plate 26 and carried on an arm' 27. As a means for attaching the door to the arm, I have herein provided a bolt ,28 passing through both, and encircling this bolt is a suitable spring 29, interposed between the plate 2b and the arm 27 andv constantly tending to move the door? 25 away from the arm 27 tor purposes' which will presently appear.

The doorcarrying lever 27 is herein pivoted on a pin 30, and isinterposed'between a p'air'ol ears 31. and rigidly secured thereto. As ameans tor normally holding the door open and automatically returning it to its'open position alter having been closed, 95 I may provide any suitable means, suchl as a spiral spring 32, attached at its inner end to the pin and its outer end to the arm 27, although in the case of a downward discharging terminal this spring may be omitted if desired, anc gravity alone relied upon to open the door. Pinned to the arm 27 is a buier pad 33 and opposite it is a steel plate 3l projecting somewhat beyond the end ot rm 27 for purposes as hereinafter eX- plained.

The hinged end of the arm 27 is formed into a fork 35 and within this fork and free to rotate on the pin 30, is the valve li'lter cam 36 on one end of which is the notched extension 37. The opposite wedge-like end 38 oi the cam 35 is arranged to engage the head 39 of the valve stem 22. Spanning the ends of the fork 35 and secured thereto is a plate 40. Obviously, if the arm 27 is moved to the dotted position 27 ,the plate 4l() will first en gage the extension 37 on the cam 35 and then rotate the cam 35, thereby lifting the valve stem 22 and moving the valve 2O from its seat 21, thereby setting up a flow ot air from the pipe 17 into the chamber 41 and through the passagesAl-2 Fig, el) into the chamber' 42 and beneath the opened valve 20 to the chamber 18 to the transit tube 9. The air also passes through the small hole 43 to the chamber 44, which is closed at one side by the flexible diaphragm l5 in the arrangement l' am describing and have shown in the drawings.

Attached to the diaphragm 45 is a bellcrank lever e6 supported at one end in a yoke 47 and pivot-ed at its other end on a pin 48 passing through and supported in a pair of ears 4-9 extending from the ring 50. This ring 50 is preferably secured to the main casting of the terminal l() with screws and servesto clamp the diaphragm Ll5 in place and to prevent leakage ot air from the chamber 44. The catch 5l on the lever 45 is located to engage the extension 34 on arm 27 when in the dotted position. Obviously `the force of the air pressure in the chamber lf'l on the diaphragm e5, pushing on the free end ot' the lever 1lb, will lock the arm 27 in its dotted position, sealing the normally open end olt the transit tube 9 with the door 25 and the external pressure of the spring 29 against the air pressure in terminal l0.

VA handle 52 is pivotally supported by pin 30 and has an extension 53 'faced on the inside with a butler 54. A spiral spring 55 tends to rotate the handle 52 as hereinafter described, having its inner end secured to the pin 30 and its outer end to the under sideolt the handle 52. l

lilxlending trom one sideJ of the handle 52 is an ear carrying a stud 5G, located in relation to the pin 30 as indicated by the dotted lines 56 in Figure 2. Extending from this stud 56 is a link 57, on the other end of which is pivoted the piston GO by means of the pin 58 and yoke 59. in cylinder 6l.

lt will now be clear that if the handle 52 is manually rotated toward the end of the transit tube 9, it will first engage. with the butler 33 on the arm 27, which may in this manner be moved to the dotted position 27 to seal the outlet Jfrom the transit tube 9, it will also rotate the cam 36 to establish an air flow through the transit tube for the propulsion ot carriers therethrough; and it will admit air pressure to the diaphragm 45 to lock the arm 27 and the door 25-26 in closed position.

Screwed into the main casting of the terminal l() is a plug 62 which fills the opening at the top of chamber 42 provided to permit machining the seat 2l and to give access to the valve 20. To the shank 63 extending from the plug 62, is secured a bracket 64 held in place thereon by a screw or pin 55 passing through a hole in the bracket Ge into the shank 63. On the bracket 64 I prefer to provide a male thread 66 and lonto this screw the cylinder 6l.

rlhe handle 52 being rotated to the dotted position 52 or beyond, and then released, it will be forced back to its normal position (shown in full lines) by the spring 55 and the movement of handle 52 will move the piston back and forth in the cylinder 61, the piston being linked to the handle.

` From the end of the cylinder (il, beyond the piston 60, is a passage 67 leading to the atmosphere and into which is inserted a check valve and timer casing 68. lithin the casing 63 is a passage 69 in communication with the passage (i7. The upper end of the passage 69 is covered by a check ball 7i) tit-ted to seat on and seal the passage 69. 'llo retain the ball 70 in the casing 68, a plug 7l is provided, having a hole 72 through its center. The lower end ot the casing 63 is shown fitted with a screw plug 7 3 and cut in the side of this plug 73, is a V groove 74 to serve as an air port for the passage of air into the passages 67 and 69. The shape of the groove 7lpermits a nice adjustment o the port area by the distance the plug 7 3 is screwed into the housing 68.

The handle may be'i'reely rotated toward the transit tube, because the air in the cylinder 6l will be forced by the piston G0. through the passages 67 and G9, past the check ball 70 and out through the hole 72. The return of the handle 52 to its normal po- The piston slides sition however, can be timed by the location of the plug 73, which deter ines the amount of air the piston 60 may draw through the groove, or port 7e per unit of time and this unit of time is usually about equal to the timeJ required to propel a carrier from one end ot the transit tube 7 to the other end.

@n the side of the terminal l0 is a rod 75 supported by an ear 7 6 near its lett-hand lll() lill) end as viewed inFig. l andr at the other end in a hole 77 through a boss 78. The lett hand extremity ofthe rod 75 is normally in engagement with the extension 53 ot handle 52, while its right hand end is connect-ed to a valve 79 engaageable with a seat 80 in the end of a passage S1 leading trom the chamber 44. Screwed onto the end ot the boss 78 is a cover 82 through which are holes 83. Between the inner end ot' the cover 82 and the valve 79 are a spring 84 and washers 85. The spring Slftends to seat the valve 7 9 and the tension ot' this spring may headj ustedy by the number and thickness ot' washers 85 to` balance the air pressure on valve 79 when it is closed on its seat 8O and the terminal is in operation.

Then the handle 52 returns to normal position the extension 53 engages the rod 75 and the tension oli spring 55 being by design sufficient to overcome the springV 84, the val-ve 79 is pushed from its sea-t, permitting the escape ot air trom the chamber' A through passage 8l and holes 83 to the at mosphere tast-er than compressed air can enter through the small hole d3, thereby destroying the air pressure on the diaphragm e5 and causing the release ot arm 27 which then is returned to normal position by gravity or the spring 32, or both7 as may he desir-ed.

lt will be clear that the release ol air pressure from the upper side ot diaphragm Ll5 permits the weight of the gate member 27 assisted by the spring 2S) to release the member 34 ot" the gate trom the catch 5l whereupon the gate swings down to `its open position.

rlhe chamber il is preferably provided with an additional outlet to permit the escape ot' air therefrom under certain conditions. Referring to lligs. l and 5, the valve casing is shown as provided with an outstanding boss 86 having an upper` chamber which communicates with the chamber el by means of a. restricted passage 91 and having a lower chamber or cavity which opens'treely into the outer ai r. These chambers are separated by a. partition having a central guide aperture therein for the reception oit' the guiding stem of a valve having a. head 90 disposed in the upper chamber ot' the boss 86. This head normally rests upon an annular seat surtace at the upper end ot the aperture and the guiding stein lits loosely iu the aperture to permit leakage past the stem when the head is raised. from its seat.

T he bottom wall ot' the lower clian'iber in the boss is furnished with asmall opening` 87 aligned with the guide aperture which receives the stem ot the valve 90. The opening 87 connects the chamber dlwith the lower chamber ot the boss 86. T he opening S7 is norn'ially closed by means or" a disk valve 88 which is held seated during nor mail operating. conditions by means ol" a oom-v pression spring S9 which is interposed be tween this dish valve 88 and the lower end of the stem ot the valve 90.

Under normal conditions the valve 90 is forced on its seat by the pressure in the upper chamber ot the boss and the spring 89 is under suthcient compressive stress to hold the valve disk 88 against its seat, the eiilective area. ot the valve disk 88 being less than the normal effective area of the valve head 90.

The air which acts upon the upper endj ot the valve 90 enters through the hole (3l, the size of which is suliicient to overcome the loss at normal pressure past the valve 90 when the valve 90 is open. ll his valve 90 and its cylindrical body may be considered as a piston7 the body oit this valve litting loosely in its bearing so that air may l ali past it when the upper end ot this valve is unseated. Both the head and the body ot the valve 90 are ot greater cross-sectional area than the port 87. Normally the air pressure per square inch on the head of the valve 90 and ou the valve dish 88 is the same. rlhis pressure as above stated is normally sutllcient to compress the spring S9, but it' the pressure in the transmission syste-1n tails below normal due to operation or" transmission lines in eX- cess ot the number tor which the pump is designed the pressure on the valve 90 will drop and the pressure ou the spring 89 will thus be relieved.

Under these conditions the valve 88 tlutters and opens slightly so as to spill air from the small chamber lil laster than air can pass the small hole 83 under the reduced pressure. In practice a very small release o? pressure on the diaphragm releases the door lt is necessary to exert some pressure on the valve 88 in order actually to seal the port 87, but the valve 55S never nieves tar from its seat.

llilhen` the head of the valve Q0 rises the available downward torce is governed by the area off the cylindrical portion of the valve and the leakage past it. fis the dish 88 is relieved of the spring pressure the very slight rise ot this valve increases its etlective pressure so that the upward and downward forces acting upon the spring are not suliistantially dillferent in value.

p lllhen a normal pressure is restored in the s vstenfi the valve 90 moves downwardly comN pressing the spring andcausiug the disk to approach more closely to its seat whereupon the ellective inessure rapidly lessons and the valve 88 isv lirmly seated This seating' ot the valve 88 is facilitated by the tact that following the door release and consequent closing olI the main valve 2O there no pressure in the chamber llwhile normal maximum pressure acts on the valve 90. rlhus the valve 90 acts with relatively greater torce downwardly than that acting upon the lll() disk 88 tending to push the latter upwardly and the disk is thus readily forced to its seat.

In single tube pressure systems, it is not the practise to provide air pump capacity sufhcient to operate all the lines in the system, so it can happen that more terminals are cut into service than the pump can supply, creating a load condition beyond the capacity of the pump.

It' too high a pressure is maintained in the system, the carriers will travel with such force, the bends may be driven out of the usual type of sleeve coupling used in the art, a particularly serious matter it' the separated jointV is in a concealed place. To prevent these conditions l have provided the valve mechanism shown in Figure 5, to automatically preventV closure ot the transmission tube it the operating pressure drops below a determined point and the adjustable tension spring 84: to release the pressure ou diaphragm A15 and thereby release latch 46 and allow the valve 2O to close to automatically cut ott the air, if the operating pressure exceeds a sate limit. Carriers lett iu the line by the operation ot either ot these satety devices, will pick up and be discharged the next time the line is used.

- As a means to regulate the air pressure in the transit tube, I employ a sleeve 92 having` openings ot a. size and location corresponding with the holes 19 in the transit tube 9. By rotating,I the sleeve about the transit tube, the effective size of the openings through which air passes into the tube 9 rom chamber 1S, can be adjusted to meet the requirements ot` the individual line on which the terminal is used. Having been adjusted, the sleeve 92 is then clamped in place on the transit tube 9 by means of the clamp couplinu` 93, secured by the screws 94.

rllhe air supply pipe l? is joined to the terminal by means ot the ball 95, shown in Figui-e2 with a 90 degree segment omitted, which is screwed onto the pipe end and fits the seat 9G in the terminal l0 and is scaled therewith. by the threaded collar 9T.

To dispatch a carrier, `it is inserted into the transit tube 9 and the handle 52 swung,r

to place the door over the end of the` tube and to crowd the projection 34 past the catch 4G where it will be held by reason ot' the air pressure on the diaphram 4ta, which jjiressure will have been established, together with a carrier propelling,i air flow, by the opening ot the valve 2O in the act ot closing.

the door as hereinbetore described.

The handle 52 beingv released, it will return to its normal position as rapidly as air can enter the dash pot through the port 74.

the handle nearly reaches its normal position, it engages the rod 75, venting the chamber 44. thereby uulatching the arm 2T, which will immediately swing to its normal position against the handle 52, releasing the valve 20 to cut ott' the air flow which will have been maintained sulliciently long to deliver a carrier, as previously explained.

Having thus described my invention, what l claim and desire by Letters Patent to secure is:

l. ln a pneumatic dispatch tube system, a transmission tube, a closure member :tor an end ot the tube, movable means separate 'trom the closure member for engaging and moving the closure member to carrier-transmitting position, fluid pressure means made operable by pressure fluid in the tube system :tor holding the closure member in carrier-transmitting position and time controlled means independent ot the pressure in the tube system for releasing the liuid pressure in said holding means to release said closure member at the end ol` a predetermined interval ot time.

2. ln a pneumatic dispatch tube system, a. transmission tube, a hinged closure member tor an end ot' the tube, a manually operable hinged closure opt-matingv member for moving said closure member into carrier-trans- Puttingl position, tluid pressure means made operable by pressure fluid trom the tube s vstem 'tor holding` the closure member in carrier-trausmitting; position, and fluid pressure operated time controlled means independent of' the pressure in said tube system tor retardiru;` the return n'lovement ot' the closure operating member to normal position, and means operated by said closure operated member when its i'iormal-position has been reached 'for releasing said holding means to thereby release said closure member.

3. lower control apparatus for a pneumatic dispatch system having a transmission tube and means tor creating; a carrier propelling air current therein, said appara-v tus comprisingi a ca 'ng provided with a socket tor the rec ption ot the end ot the transmission tube and a chamber communieating;- with the tube through an opening in the side wall of the latter, a normally open pivoted cover for the end ot' the tube, a, normally closed valve tor coutrollinl admission ot pressure fluid to the chamber` a rotary valve litter turning' "freely about the axis ot movement ot the cover and independent ot the latter, and lost motion connections between the cover and said rotary valve litter tor moving` the latter as the cover approaches its closed position and thereby opening said controlling,r valve.

fl. Power control apparatus for a pneumatic dispatch system having a transmn5 sion tube and means for creating; a carrier propelling' air current therein, said apparatus comprising a casing provided with a socket t'or the reception ot' the end ot the transmission tube and a chamber communieating with the tube through an opening' in the side wall of the latter, a normally open itl() pivoted cover for the end of the tube, a normally closed valve tor controlling admission oit' pressure 'fluid to the chamber, a rot-ary valve litter turning freely about the axis ot moven'ient of 'the cover and independent of. the latter, said actuator having a shoulder at one side of its anis and a valve lifting cam at the other side ot its axis, and a member partaking of the swingingmovement of the cover normally spaced `trom the shoulder ot thc actuator but engageable with said shoulder as the cover approaches closed position and thereafter lifting the valve as the cover completes its movement.

Power control apparatus for a pneumatic dispatch system having a transmission tube and means for creating a carrier propelling air current therein, said apparatus comprising a casing provided with three sockets arranged side by side, the central socket extending entirely through the casing and being adapted to receive t-he end portion oit the transmission tube, one of the lateral sockets receiving the endk oi an air supply pipe and the other socket receiving a removable plug supporting a timing device, said casing having a chamber into which the lateral sockets open, a normally closed valve controlling a passage between said chamber and a second chamber which in turn communicates with the transmission tube by means ot an opening in the side wall ot the latter, a normally open cover for the end et the transmission tube, means actuable by the cover in closingto open said valve, and means controlled by the dash pot for terminating' the period during which the cover remains closed.

6. Power control apparatus tor a pneumatic dispatch system having a transmission tube and means tor creating a carrier propelling air current therein, said apparatus comprising a normally open cover tor the end ot the tube, -fluid pressure controlled latch means for retaining the cover in closed vposition during the transit of a carrier through the tube, a handle device independent of but engagea/ble with the cover lor moving the latter to closed position where it is held by the latch, said handle tending to return to normal position after the cover is closed, a dash pot having a piston connected to the handle, said dash pot havingvalved air ports arranged to permit tree movement of the handle in closing the cover and to retard return movement of the handle to normal position, and a pressure reliet valve actuable by the handle as it reaches normal position to cause release of the cover holding latch.

7. Power control apparatus tor a pneumatic dispatch system having a transmission tube and means for creating a carrier propelling air current therein, said apparatus comprising a normally open cover for the end of the tube, iuid pressure controlled latch means for retaining the cover in closed position during the transit of a carrier through the tube, a handle independent of but engageable with the cover tor moving the latter to closed position where Vit is held by the latch, said handle tending to return to normal position after the cover is closed, a dash pot cylinder, a piston in said cylinder, means connecting the piston to the handle, an air control casing connected to one end of' the dash pot cylinder, said casing having a chamber communicating with the cylinder, ports for said chamber, a valve permitting tree egress oi air from one port but preventing ingress oit air through said port, an adjustable valve permitting a regulable amount of air to enter through the other port, said air control means permitting tree movement of the handle in closing the cover and ret-arding return movement of the handle to normal position, and a pressure relie't valve actuable by the handle as it reaches normal position to cause release ot the cov-er holding latch.

8. Power control apparatus tor a pneumatic dispatch system having a transmission tube and means for creating a carrier propellingl air current therein, said apparatus comprising a normally open cover for the end ot the tube, fluid pressure controlled latch means for retaining the cover in closed position during the transit of a carrier through the tube, and means for rendering the latch means inoperative when the pressure in the system is too high tor effective operation.

9. Power control apparatus tor a pneumatic dispatch system having a transmission tube and means :tor creating a carrier propelling air current therein, said apparatus comprising a normally open cover for the end of the tube, Huid pressure controlled latch means for retaining the cover in closed position during the transit of Va carrier through the tube, and means for rendering ,the latch means inoperative 'when the pressure in the system is too low tor effective operation.

10. Power control apparatus for a pneumatic dispatch system having a transmission tube and means for creating a carrier propelling air current therein, said. apparatus comprising a normally open cover for the end ot the tube, `fluid pressure controlled latch means for retaining the cover in closed position during the transit of a carrier through the tube, and means rendering the cover retaining means inoperative when the pressure in the system is either above or below that necessary for eilective operation.

1l. Power control apparatus for a pneumatic dispatch system having` a transmission tube and means tor creating a carrier propelling air current therein, said apparatus comprisingv a normally open @over -for the sure controller Afor the Cover retaining latch eml of the tube, fluid pressure controlled whereby to render said latch inoperative latch means for retaining the cover in closed when the pressure in the system falls below position during the transit of a carrier normal.

through the tube, and means comprising a In testimony whereof, I have alxed my pair of Valves of relatively dierent area signature.

controlling the operation of the luicl pres- JAMES G. MACLAREN. 

